The invention relates to a toner replenisher and method for an electrographic imaging machine, including flow of toner through a toner replenisher and sealing between a toner replenisher and a toner bottle.
In a typical electrographic imaging machine (e.g. copier, duplicator, printer, etc.), for example an electrophotographic imaging machine, a continuous loop of photoconductor film may be used to transfer an image from an input section onto a receiving medium (e.g. a sheet of paper or the like). The film is charged and passed through an input section where an image (i.e. analog or digital) is projected onto the charged film. The film then moves through a developing section where toner (i.e. dry ink) is applied to the charged image before the image is transferred to the sheet of paper. The paper is subsequently passed through a fuser section where the toner is fixed to the paper by passing the paper between a pressure roller and a heated roller.
Before applying the toner to the charged image, many electrophotograpic machines mix the toner with a carrier to form a two-component developer. When using two-component developers, it is necessary to maintain a desired ratio of toner to carrier; this ratio being commonly known as “toner concentration” or “TC”. Typically, the TC may range from about 2% to about 14% by mass for general printing applications. However, the actual range of the TC may vary over different ranges depending on the densities and/or relative size of the particular toner and carrier particles being used.
To maintain the proper TC in a particular machine, the toner typically flows from a source (e.g. a bottle or other container) into a mechanism known as a “replenisher” which, in turn, feeds the toner to the developer at a desired rate. Since the charge of toner dictates other process settings within the printing/copying machine, a replenisher that maintains a consistent and controllable flow rate of toner to the developer throughout the printing operation is very desirable. Replenishers are described in U.S. Pat. No. 5,229,823 and U.S. Patent Application Publications U.S. 2002/0071692 A1 and 2003/0002890 A1, the contents of these three publications being fully incorporated by reference as if set forth herein.
Toner has a tendency to bridge in the replenisher. Bridging is a state where the powder becomes a self-supporting mass and resists flow through the replenisher due to the tendency of the particles to support each other or to adhere to each other within the replenisher. This can interrupt toner flow through the replenisher and adversely effect toner concentration.